#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <math.h> 
#include <ctype.h> 
#include <time.h> 
#include <assert.h>

int main()
{
	int arr[9] = { 1,2,3,4,5,4,3,2,1 };
	for (int i = 0; i < 9; i++)
	{
		int flag = 1;
		for (int j = 0; j < 9; j++)
		{
			if (j == i)
				continue;
			if (arr[j] == arr[i])
				flag = 0;
		}
		if (flag)
			printf("%d\n", arr[i]);
	}

	return 0;
}